Diseases of the Endocrine Glands - Anterior pituitary gland

The anterior pituitary gland, also called the
hypophysis
, is located in the center of the brain. It produces two types of
secretions: a growth hormone and hormones that stimulate certain other
glands.

The anterior pituitary gland is subject to neurochemical stimulation by
the
hypothalamus
, a nearby part of the brain. This stimulation results in the production
of the hormones that promote testicular and ovarian functioning, and
does not occur normally until around 12 years of age in girls and 14 in
boys. The beginning of this glandular activity is known as the onset of
puberty
.

Puberty is sometimes delayed for no apparent reason until age 16 or 17.
Because the hypothalamus is affected by emotional factors, all of the
endocrine glands governed by the anterior pituitary can also be affected
by feelings. Psychological factors can therefore upset the relationships
in the glandular system and produce the physical symptoms of endocrine
disorders.

It is extremely rare for the anterior pituitary to produce too much or
too little of its hormones, but sometimes hypofunction may follow
pregnancy because of thrombosis or changes in the blood vessels.

A truly hypofunctioning anterior pituitary gland can cause many serious
disturbances: extreme thinness, growth failure, sexual aberration, and
intolerance for normal variations in temperature. When appropriate
diagnostic tests determine the deficiency, the patient is given the
missing hormones in pill form.

Absence of the growth hormone alone is unknown. Most cases of
dwarfism
result from other causes. However, excess production of the growth
hormone alone does occur, but only rarely. If it begins before puberty
when the long bones are still growing, the child with the disorder will
grow into a well-proportioned giant. When it begins after puberty, the
head, hands, feet, and most body organs except the brain slowly enlarge.
This condition is called
acromegaly
. The cause of both disorders is usually a tumor, and radiation is the
usual treatment.

The thyroid, adrenal cortex, testicles, ovaries, and pancreatic glands
are target glands for the anterior pituitary's stimulating
hormones, which are specific for the functioning of each of these
glands. Therefore, a disorder of any of the target organs could be
caused either by an excess or a deficiency of a stimulating hormone,
creating a so-called
secondary disease
. There are various tests that can be given to differentiate primary
from secondary disorders.

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